I have a couple of strangely suspended turntables. One is a Maplenoll Ariadne Signature. It has a linear tracking arm and platter both supported by air pressure. Like an air hockey table. The compressor is about the size of a mini fridge, and lives at the other end of 250′ of 1/4″ air line. In between are several black plastic columns from 1.5 to 4 feet in length that smooth out air pulses. The table itself is too heavy to move without disassembly. Oh, and it also has a movable trough full of oil that the end of the tonearm drags a puck through for damping. I’d get rid of the thing if I could get it out of the closet where it’s stored without significant dismantling of the shelves or doorway.

Regarding concrete, earthquakes and Japan, one hears stories of well heeled Japanese audiophiles having a separate support footing poured just for a turntable. Done right, this is supposed to go down to bedrock and be physically isolated from the house structure. Good idea, but with all that seismic activity, aren’t you inviting tremors to be reproduced by your cartridge?

A few years ago I did some minor tech work in a DJ booth in one of my Students’ Union bars. They’d taken a budget approach to a very similar system: each turntable was bolted to a paving slab. This slab sat on a half-inflated bicycle inner tube, which in turn sat on top of a second paving slab.

Not quite in the same league as the product above, but the tech guys and DJs swore by them. IIRC the paving slabs were rescued from a skip, so the total cost of each mount was about Â£4.